DEVIATOR breaking boards?
Vu Thien An J V
--
John Vu
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Fischer Michael P
Hey there,
I was fully intending to buy a deviator for my new board which
has a decent flip tip on it. When I was in Hatteras, I was told
by numerous people that a bigger concern is that when using a
deviator, the mast track may rip out. This is from a gigantic
pullout force caused by the mast smacking on the deviator. I never
saw anyone using one in Hatteras. I decided I'd rather take the
risk of dinging off the nose as opposed to ripping out the mast track.
I'll give a little theoretical background to what happens.
It's a simple momentproblem:
Force 1> !
V
mast> -------------------------------------------------
Deviator> ^ ^
!
Resultant Force 2 at universal
Let's just say for example that you wipe out and let go of your rig.
It flies directly towards the board's nose with a force of, who knows?,
1000N. Assuming this force is centered about halfway up the mast,
at a length(1) of 220 cm. Now, if it smacks the Deviator dead on...
the contact point on the deviator is around 20cm from the attachment
point of your mast base, this would cause a whopping pullout force of
approximately 11000N.
This is solved by: Sum of the moments about the deviator equals zero.
This means that:
Force(1) * Length(1) = Force(2) * Length(2)
where Force(1) is the force of the sail being slammed
Length(1) is the length from the center of the force to
the deviator
Length(2) is the distance from your base to the deviator
Force (2) is the resultant pullout force.
That's about right. Anyways, mast tracks are not installed to withstand
those large pullout forces. Thats why they can rip out!
So anyways, in my opinion, Deviators might not be so great!
FISH (Apparently I'm quite an engineering geek)
Gil Woolley
I bought two Deviators, one for myself and one for my son who is a much
better sailor. We both had the requisite number of dings and crunches to
prove that the mast will damage the nose (bow). Since we installed the
Deviators, we have not done further damage to the bow. We have not
pulled out a mast track.
I suspect that there are some things not wrong but over-simplified with
your analysis that cause you to come to the wrong conclusion.
The mast seldom hits square on. The (pre Deviator) dings are typically
on one side or the other, not right on the tip. There is a roller on the
deviator which would tend to deflect the bow away from the side that the
mast is falling on.
The mast is attached to the mast track not with a rigid pinned pivot but
a rather flexible hourglass. This can stretch significantly at the time
of impact and spread the time from an infitesimal out to many
milliseconds. By spreading the time, the force required to move the hull
decreases substantially.
The bow does not have to be pushed under water. The effect of the large
forces may just as easily pry the stern of the hull out of the water.
Again, the forces may only need to push to bow sideways rather than
straight down.
The hull probably flexes in such a way to reduce the pull out force.
Maybe the Deviator also flexes in a minor way to reduce the peak forces.
The lower part of the mast may also flex in a minor way.
The chief repair honcho at ASD replied to my question of how to prevent
damage to the bow by suggesting that I learn not to fall. For some
reason, I haven't been able to apply that advice.
Good engineers test their theories. My theory is that the cost of the
Deviator will be repaid in lower repair bills or repair time. So far
that is proving to be true. I don't sail at Hatteras and I'm sure that
there are others who can put more strain on a boat than I. When the
theory proves wrong, I know where there is an excellent article on how
to put a new mast track into a hull. Not an easy task, but not
impossible. So far, I'm many crashes ahead thanks to the Deviator.
Gil Woolley
Harold Blakney
FWIW
I use a deviator when I use the large sails on large boards and it works
fine. When you go over the handlebars, it will move the board away from
the impact of the mast. I know that it has saved me at least one repair
to the nose.
I do *not* use these in the waves (even with the flip tip wave boards)
because they prevent the needed capability of swinging the mast over the
nose to get the sail in the right position for a fast water start. You
have to push the nose of the board down to get the mast over it and that
wont cut it with a wave bearing down on you.
The deviator has its place and I suspect that slalom sailing with the
fragile nose boards is an ideal application.
Harold
Chris Setchell
John:
Where you making a comment, describing an experience, asking
a question or what with your posting?
My retailer tried to sell me a Deviator when I bought my new
Seatrend. I declined. I figured I could control the mast
sufficiently away from the nose of my board and I was
worried that a slam with sufficient force to break the nose
of the board might crack a carbon mast from compression
between deviator and mast base caused by lever action of rig
with 200lb body in harness with plenty of forward momentum
even with a mast base protector. Never thought that this
compression could also stress mast track area.
Do you - or anybody out there - have a positive/negative
experiences with this product? What sort of usage guarantee
does the manufacturer provide - will they replace damaged
masts or boards caused by correct use of Deviator?
Chris
Paul Scrutton
I recently bought a new Seatrend and enquired about the deviator
with the Seatrend dealer at Hatteras. He mentioned that he wasn't
sure that it was a good idea, citing the mast track reason. He
didn't sell the product either.
I noticed that Deviators were installed on all of the Axxis's at Happy
Surfpool in Margarita. I wonder if these kind of rental operations
have any data on the long-term use of the Deviator.
I was sufficiently intrigued still, enough to go out and buy one
anyhow. I found that I couldn't install it with the Chinook low
mast base that I use, at least not without replacing the screws
that held the mast base onto the board. This was a rather
unattractive proposition, as the screws have a hex head that enables
the universal to adjust them, so I went ahead and returned the
Deviator to the store.
--
Paul Scrutton
USWA Member US-292
My views may not agree with those of employer.
Benny "klimpen"
Klimpen
Hi I'm a Windsurfer from sweden who just wants to know
what a Deviator is, call me stupid but I have never heard of it.
I kinda figured it out but I'm not sure.....I think it has something to do
with protecting the nose of the board
but I dont understand how........? ? ? ? ? ? ?
END
ellen faller
With regard to the Deviator, my guess is that they save waaaaay more boards
than they do rip out mast tracks.
We were in Aruba in Dec 96, at Vela and they had Deviators on all their boards
and had found that it saved $$$ in the cost of board repairs and it kept far
more boards in the fleet than without the thing. Given the amount of usage
their boards get, from all levels of sailors, (and some of them were doing very
energetic crashes...), if they were happy with them, the things must work.
Now, from my personal perspective, I would not use one myself after spending
most of a week with one on the boards I used. I didn't crash all that much and
it was usually in some other way. Furthermore, it sits right where I put my
foot when tacking a shortboard, and it took some practice to deal with this
inconvenience. It also made getting the rig over the bow of the board to set
up for a waterstart *very* difficult. One guy who was there at the same time
we were managed to kill 2 Deviators in this fashion, altho his board was just
fine!
If you crash alot and are in the habit of damaging the nose of your board,
then it is a great thing and does not seem to harm the mast track, altho the
data are not in from extended use.
Ellen
:
: I was fully intending to buy a deviator for my new board which
: has a decent flip tip on it. When I was in Hatteras, I was told
: by numerous people that a bigger concern is that when using a
: deviator, the mast track may rip out. This is from a gigantic
: pullout force caused by the mast smacking on the deviator. I never
: saw anyone using one in Hatteras. I decided I'd rather take the
: risk of dinging off the nose as opposed to ripping out the mast track.
stuff clipped here):
: FISH (Apparently I'm quite an engineering geek)
:
Ken Nelson
Just some physics thoughts, cos I haven't personally tried a Deviator:
1) The nose damage (ding or fracture) is normally due to the speed of the rig
nose slamming into the board
2) The Deviator is both more durable than a board, and has the deformable
roller, so it will survive the mast impact. The force of impact is turned into
a distributed moment which is dissipated in sinking the nose/lifting the stern
(if the reports of mast tracks being ripped out is true, then maybe boards
still can't survive the impact; maybe whatever deviation device should absorb
more of the force...maybe even some sort of sacrificial impact absorber?)
3) Tie yer teddybear to the nose of yer boom?? (Seriously, do booms have to
have pointy bits that will damage the board?)
In article <337AEA...@idirect.com>, setc...@idirect.com (Chris Setchell)
wrote:
Waubesa767
I first tried a deviator on a rental board in Aruba at Roger's ( the one
who also invented the deviator) and was impressed. I was launched a few
times where there may have been damage to my slightly fragile Mistral
Screamer, but there was none. Roger told me though that they are not
foolproof. If you open up the sail during the launch, the boom itself not
the nose of the boom can then hit the board and still hole it if you were
going fast enough (thru the air)!
I bought one and it has so far protected my board. It does stick up
a little though just in front of the mast and sometimes makes manuvering
the board during a waterstart a little more cumbersome because it gets in
the way.
Dave
ar...@village.ca
Just to clarify my original post.
I was not so concerned about riping the mast base out of the board with
the deviator.
My experience is that after one week of hard sailing in Margarita with
my Fathom board (which is bullet-proof to shock except for sharp
punctual shock), leaving the deviator in the exact same position on the
mast track for the week, the repeated pounding of the mast on the board
was enough to crack the forward section of the rail (not the nose) on
BOTH side.
I had a mast protector on but obviously it was not long enough to
protect the rail of the board.
I have no problem with the Deviator protecting the NOSE of the board,
however I really am concerned about it causing reapeated trauma exactly
to the same forward sections of the rail, especially when you do not
need to move the mast track.
Hope that's clearer.
Happy sailing with bras...boom bras.
John Vu
Mike & Tammy Sainz
I love the Teddy Bear idea. I'll ask my 13 year old daughter.
Seriously. I have 4 ProTech which I have demo'd 25 - 30 times and I
won't let them out without one of the 4 Deviators I own.
By the way, the Deviator is another great product from John Parton of
ProTech and there are four problems/solutions.
1) They are where you often step to tack but as the doctor would say
"well don't step there"
2) They are difficult to swing the rig over the front of the board so
now I always water start and jibe instead (except when racing). My wife
did damage the first one in '96 this way
3) They appear to load the mast track, but only if you figure out how to
slam the nose while stil in the strap with weight on your feet.
4) They require using the rear hole for the universal screw on uni's
that have the off center screw so the handle rotates all the way around.
All in all the only real problem is #4 if the board requires your sail
all the way forward as in a huge older sail on a newer board with the
track installed towards the rear of the board. Any of the newer sails
are power forward and are designed to be in the middle of the track.
Vela Tom and I both wished I had one on the 8'7" Seatrend Accelerator I
ran into the sand bar in Margarita. I could have bought almost 3 for the
repair cost of the nose I had in my pocket and kept them.
Ken Nelson wrote:
>
> Just some physics thoughts, cos I haven't personally tried a Deviator:
>
> 1) The nose damage (ding or fracture) is normally due to the speed of the rig
> nose slamming into the board
> 3) Tie yer teddybear to the nose of yer boom?? (Seriously, do booms have to
> have pointy bits that will damage the board?)
>
> In article <337AEA...@idirect.com>, setc...@idirect.com (Chris Setchell)
> wrote:
>
> >Do you - or anybody out there - have a positive/negative
> >experiences with this product? What sort of usage guarantee
> >does the manufacturer provide - will they replace damaged
> >masts or boards caused by correct use of Deviator?
> >
> >Chris
--
mailto:zi...@cyberramp.net (US-097)
Mariner Sails/Team ProTech & Windwing/Shredman & WindIGo Sportswear
W'surfing is like a box of chocolates, get the good stuff and eat fast.
Eyes4Hire
Paul Scrutton wrote:
>I was sufficiently intrigued still, enough to go out and buy one
[deviator]
>anyhow. I found that I couldn't install it with the Chinook low
>mast base that I use, at least not without replacing the screws
>that held the mast base onto the board. This was a rather
>unattractive proposition, as the screws have a hex head that enables
>the universal to adjust them, so I went ahead and returned the
>Deviator to the store.
I use the deviator with a two bolt Chinook base. It is a pain in the butt
to get the base on with the deviator but it is possible. You have to wedge
a piece of a twig or some gum or a spit wad under the nut when you drop it
into the track so that it is sitting higher up in the track. The bolt
should then be just long enough by about a hal a thread. This system is
fine if you don't remove your base with any regularity. It sucks if you
are going to pull up to the site on a windy day and spend 10 minutes doing
surgery while everyone else is shredding. My deviator has not damaged my
track, but the spinner is gone after about a dozen sessions.
Peter
Tyler P. Hoffman
Ibroke my deviator after 2 sessions - they are not worth it unless they are
made stronger - I don't use one anymore...
Tom
After whacking my Explosion II nose with the boom at least
one time per sesson (always hitting the boom JUST BEYOND the
boom bra against the rails right at the nose of the board),
and having cracks in the nose repaired once, I bought
a deviator. Since I put it on, I have never hit the nose or rails
with the boom. No sign of stress in the mast track yet.
I like it, my board seems to like it.
Tom
Chris Setchell
From an ex-engineering geek:
Regarding your math - If I'm not mistaken the force, because
it's a lever, would be proportional to the square of the
distance. [Excuse me if I'm wrong, I haven't done those
problems for a couple of decades - and who knows, physics
may have changed in that time.]
Chris
Tyler P. Hoffman
I had a deviator and the mast broke it so they are not worth much in my
book...
Tyler
Waubesa767
>I had a deviator and the mast broke it so they are not worth much in my
>book...
I just purchased a new deviator in Aruba and they have made a change
to it to beef it up a liitle bit. The old one was rounded at the base
where the roller mount meets the base. The new one comes to 2 points and
is suppose to dissipate the load better to save the deviator..
As to the load problem for you Physics majors, remember the board is
floating, if you have been launched the rig weighs maybe 10 lbs and a lot
of the force will be used in the sinking of the board at the time of
impact.
I have 14 days of sailing so far on a screamer with no damage to
either the deviator or board
Dave
Mike & Tammy Sainz
I just sailed the obstacle course for the US Open so picture this.
Overpowered on a 6.8, I get a good chop hop of about 1 foot and
land....right in front of the 20 foot long sausage bouy floating across
the top of the water. I hook my 44cm racing fin square on the bouy and
do my first right down the middle hyper slam since i took 2 inches off
the Seatrend on the sand bar in Margarita.
Didn't even check to see if there was any damage since I was using a
deviator for the entire Regatta. True you have to lift the sail over the
Dev. when rotating it around the front or you can damage the plastic
posts under the Dev. however John will warantee your deviator if you
call 561/585-5033.
I'd rather spend the weekend way the hell overpowered at mach speed in 3
foot swell on a 7.4 race and never wonder if Im going to damage the
board or mast. There were enough colissions at the marks with 25 people
jibing to take care of that. Use a deviator and you can explode in front
of a 200 person crowd without any worry about damaging that 12.5 lb race
285.
Jibing will alleviate the problem rotating the sail over the front
problem.
--
GINO DELG
I've been using a Deviator for about a year and have had no problems. It's
very reassuring.
Gino, Cape Cod
Wolfgang Soergel
GINO DELG wrote:
>
> I've been using a Deviator for about a year and have had no problems. It's
> very reassuring.
To me it doesn't look reassuring but intimidating: a huge device
right where one steps when uphauling or tacking (which is
also the situation when one drops the mast most often when doing
it on shortboards. Stepping farther forward isn't a real option on a
8'9" with thin nose).
I get my feet hurt enough on normal mastfeet
and i would miss the fun of tricking around in marginal winds.
Besides : is it possible to flip the board nose under the sail before
waterstarting with this thing ?
Personally i'll stick with beefy reinforced board noses and tails --
no ding do far, even with quite thin noses.
--
Wolfgang Soergel
Lehrstuhl fuer Nachrichtentechnik phone: ++49-9131-857781
Universitaet Erlangen-Nuernberg fax: ++49-9131-303840
Cauerstrasse 7 email:
wsoe...@nt.e-technik.uni-erlangen.de
D-91058 Erlangen, GERMANY
http://www.nt.e-technik.uni-erlangen.de/~wsoergel
Gil Woolley
Wolfgang Soergel wrote:
clip
....
> Besides : is it possible to flip the board nose under the sail before
> waterstarting with this thing ?
>
> Personally i'll stick with beefy reinforced board noses and tails --
> no ding do far, even with quite thin noses.
>
> --
> Wolfgang Soergel
> Lehrstuhl fuer Nachrichtentechnik phone: ++49-9131-857781
> Universitaet Erlangen-Nuernberg fax: ++49-9131-303840
> Cauerstrasse 7 email:
> wsoe...@nt.e-technik.uni-erlangen.de
> D-91058 Erlangen, GERMANY
> http://www.nt.e-technik.uni-erlangen.de/~wsoergel
Yes it is quite easy to press the nose down and get the Deviator roller
to clear the mast. When you forget the Deviator is there, you'll not be
able to move the nose where you want it. Then you remember to push down
firmly on the nose and you can move the nose over where you want it.
The Deviator has so improved my ratio of sailing time to repair time
that I actually went out and repainted my Seatrend over the last repair.
The board looks quite well once again. Previously, I just duct taped it
or glassed it with epoxy and smoothed it knowing full well that I'd get
a new ding the next session. No new dings since I installed the
Deviator.
The best advice I've gotton from a repair guru at ASD is to learn not to
fall and you won't get dings in the nose. Somehow I keep forgetting to
follow that advice. Hopeless, I guess:)
It is not that difficult to swing the nose.
Michael McInerney
A friend was using a deviator and had a rig-board separation. It
looked like the force of the rig falling forward and landing on
the device caused the mast foot to be levered upward 'cause his
lower u-joint bolt was pulled out of the u-joint - striped the
threads. - Mike
--
invg005
I had a very mild fall which would not have done any damage to the front
of the board but ended up pulling the rubber ujoint right out of the
mastbase.
Mike & Tammy Sainz
I just returned from Aruba which is the home of the deviator and saw
hundreds in use. There were no complaints from any of the rental centers
that require the use of the deviators for beginners or for those who
dont want liability insurance. I would recomend your friend switch to
single center bolt tendon universals from windsurf hawaii, etc. that are
wave proof and fit the deviator perfectly.
P.S. I demo all 5 of my Pro Tech and won't let them go out without a
deviator on them.
Michael McInerney wrote:
>
> A friend was using a deviator and had a rig-board separation. It
> looked like the force of the rig falling forward and landing on
> the device caused the mast foot to be levered upward 'cause his
> lower u-joint bolt was pulled out of the u-joint - striped the
> threads. - Mike
>
> --
>
>
--
Kent Browning
Michael McInerney wrote:
>
> A friend was using a deviator and had a rig-board separation. It
> looked like the force of the rig falling forward and landing on
> the device caused the mast foot to be levered upward 'cause his
> lower u-joint bolt was pulled out of the u-joint - striped the
> threads. - Mike
>
> --
>
>
use the deviator. I don't think it will cause much difference on the
u-joint. But after taking the nose off of a BRAND NEW Vivace without a
deviator, I know the deviator reduces the loads on the board. I've been
slammed many times just like that famous fall, but no board damage yet.
Kent
Mike & Tammy Sainz
invg005 wrote:
Could y'all let us know what type of U-Joint, approximate age, exact
point of failure was involved. I have 4 u-j's permenantly mounted on
deviators without incident for 2 years and I would prefer to replace a
potentially dangerous u-j rather than have it go out under the Golden
Gate or 2 miles offshore in Aruba, etc.
A friend from the house in Aruba clued me in on a great fix for a small
deviator problem. Replace the flat steel nut on your universals with a
brass T-nut (std 9mm) to make it easy to put the universal into a
chinook mast track with the deviator attached, without risking the nut
unscrewing.
I had a nut unscrew and drop in the water to be lost during the HiWinds
and replaced it with a T-nut in my gadget bag. Now it goes on and off
easilly with no risk of unscrewing. Now all I need is wind to use it.
Thanks Paul.
>
> Michael McInerney wrote:
> >
> > A friend was using a deviator and had a rig-board separation. It
> > looked like the force of the rig falling forward and landing on
> > the device caused the mast foot to be levered upward 'cause his
> > lower u-joint bolt was pulled out of the u-joint - striped the
> > threads. - Mike
> >
> > --
> >
> >
> The exact thing happened to me using the deviator in Aruba this spring.
> I had a very mild fall which would not have done any damage to the front
> of the board but ended up pulling the rubber ujoint right out of the
> mastbase.
--
Paul Scrutton
In article <33A5ED...@cyberramp.net>, Mike & Tammy Sainz <zi...@cyberramp.net> writes:
|> I had a nut unscrew and drop in the water to be lost during the HiWinds
|> and replaced it with a T-nut in my gadget bag. Now it goes on and off
|> easilly with no risk of unscrewing. Now all I need is wind to use it.
|> Thanks Paul.
No problem Mike! Glad to help out. The real credit should go to
Fox Watersports of Buxton for showing me this great solution for
attaching a deviator using the Chinook two bolt base. Thanks guys.
NeauDL
Here's an even simpler idea for how not to lose the nut for your mast
foot: put it in the track, and seal it closed. I've used one-bolt
Streamlined and Chinook feet for more than 10 years. I put an 8 mm nut in
the mast track, filled in the opening in the track with epoxy putty, and
I've never lost one. My old boards have both 8 mm and 5/16 in. nuts. If
the mast foot becomes somewhat unscrewed so that it slides in the track
while sailing, it can't come out.
Mike & Tammy Sainz
What a cool idea. I had a board/universal seperation at the hatchery
last August in 6 foot swell and it tested my ability to remain calm.
Unfortunately most uni's are made with a bolt length that won't hit the
bottom of a Mistral Equipe, etc. mast track when screwed into the
optional nut built in the sliding mast track.
The deviator raises the bolt up enough so that screwing a bolt onto a
loose nut (resting in the bottom of the slot in a chinook track) is
impossible. The T'nut brings the threads up a good 1/4" and makes it
possible again.
How do you keep from loosing the roud plastic disk when you take the uni
off the board? The nut is what keeps me from loosing mine, or now keeps
the uni and the deviator in one piece in the trailer.
--